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I am aware I can send samples in for analysis, but is it possible for the average Joe to measure and determine the organic content of the grow medium with reasonable accuracy (+/-10%)? What is possible?

The sphagnum peat is also an organic component of Mel's mix. Simply put, if it was once a living thing it is considered an organic substance. Dirt is not. Vermiculite and perlite are minerals and not considered to be an organic substance.

I am using mels mix with 1/3 organic composts by volume from 5 sources. However, across the board, my veggies are low in yield and small in size, even with fertigation at each watering. For correction I intend on solarizing the beds for 80-90 days then amending the bed mix with 1.6oz/sqft each of azomite for mineral content and bone meal per an organic shop vendor recommendation.

You might try the traditional topsoil separation test as described at the bottom of the page.. Most of the organic material will float to the top. It will give you a rough idea, but not 10% accuracy. I've used this method on topsoil, but not MM.

If you're handy, you could do a burn test and burn off the organic material. Measure weight before and after.

If you suspect nutritional deficiencies, then you should have your MM tested for nutrients. You could have high organic content that is depleted.

@boffer wrote:You might try the traditional topsoil separation test as described at the bottom of the page.. Most of the organic material will float to the top. It will give you a rough idea, but not 10% accuracy. I've used this method on topsoil, but not MM.

If you're handy, you could do a burn test and burn off the organic material. Measure weight before and after.

If you suspect nutritional deficiencies, then you should have your MM tested for nutrients. You could have high organic content that is depleted.

I am new at gardening and may have incorrect concepts of 'high organic content that is depleted'. What are the 'best if used by' parameters for composts in states of being bagged and/or being blended with other composts, ready for sqft use. I've not seen that in any compost labelling in that arena, but could have missed it.

Each season (or with each sqft replanting) the 1/3 organic component blend is replenished. After that, my target is bi-monthly alternations between adding blended compost to beds and applying a 3-4-4 organic fertilizer along with 16oz of 2-2-2 through fertigation. I would like to feel the nutrient part of the equation would be solved with that, but the pudding has not revealed any proof.

@GreenGene wrote:Thank you for the informative link to soil types and testing.

I am new at gardening and may have incorrect concepts of 'high organic content that is depleted'. What are the 'best if used by' parameters for composts in states of being bagged and/or being blended with other composts, ready for sqft use. I've not seen that in any compost labelling in that arena, but could have missed it.

Each season (or with each sqft replanting) the 1/3 organic component blend is replenished. After that, my target is bi-monthly alternations between adding blended compost to beds and applying a 3-4-4 organic fertilizer along with 16oz of 2-2-2 through fertigation. I would like to feel the nutrient part of the equation would be solved with that, but the pudding has not revealed any proof.

Thanks again,

OK, there are a few mis conceptions in your post.Firstly, after the growing season you don't replace with more mix, all you add is more quality compost.Secondly, there are no industry standards for bagged compost and quality (nutrient density) is not guaranteed. I recommend using bagged compost in the same year it is purchased.

Thirdly, the quality of the compost is only as good as the variety and quality of ingredients used to make it. When making compost there should be more nitrogen than carbon in the mix of stuff to rot. Nitrogen is required, along with oxygen, to promote the composting process.

I irrigate twice daily dripping 25 to 35 gallons across 200sqft split into 4 zones (3-4minutes/zone which is the point where the tabletop beds just begin to lose water and drip themselves [deep percolation] ). The surface to 6" sweet spot root zone area must surely be saturated at that point. It looks it, and the finger poke test confirms. My target was to have a drip emitter at, or effectively close to, each plant within that plants sqft planting matrix.

GreenGene, I also live in a Zone 9A. It was 101*F today. The MM looks beautiful, and the beds and watering systems are so well built. But, something else is going on. My original MM and beds were so pretty but not nutritious so that is coming from someone who learned the hard way. Here's my Johnny-come-lately diagnosis from all the discussions so far today:

Over-watering: Your area gets 40-60" of rain per year. I got 2-3" (can't remember the total at the end) last year. You should not have to water every day much less twice a day. By mulching the top of the MM you can slow water from evaporating at the surface, yet allow the excess to drip out the bottom. If the bottom MM is saturated, there could be a lack of air in the lower Mix, or soggy feet (roots). Soggy roots can be as bad as not enough water.

Over-watering means the nutrients from the compost are going out the bottom faster than if watering occurred when it was really needed. By cutting back the watering, the slowly released nutrients from the compost will be able to hang around more and feed the plants.

Mulching: In hot zones, every drop of water counts. But you have plenty of natural water so your irrigation days will only be needed between rains. Mulching the top allows the water to more evenly distribute within the mix, side to side and top to bottom. Mulching shades the MM, keeping it cooler.

Compost: If you are buying 5 commercial composts as the blend, reading the labels is vital, critical, super important. Once the beds are filled with MM, no more peat moss or vermiculite/perlite is added. Many bagged composts have wood chips, rocks, bottle caps, peat moss, "top soil", sand, vermiculite, and other ingredients that defeat the purpose of only adding compost to refresh the Mix for the next planting. Do you screen (1/4" metal hardware cloth) the composts to remove wood chips and other large undesirable items? Is one of the 5 a good composted animal manure without peat moss or wood chips? My garden is getting healthier and healthier now that I make my own compost, complete with horse poop!

Can you list the 5 composts that you are using? That will help us try to further evaluate the situation.

Compost top dressing: The Mix in long season crops (a few months) will shrink down. Adding compost to the top will keep providing nutrients to the end of that crop's growing cycle.

Solarization: Solarization kills micro-organisms in the soil. That is great if one has harmful nematodes, but other organisms are being killed at the same time. Since you have raised beds, nematodes are probably not a problem, so don't solarize it. I think of the movie "Avatar" where all life on that planet was inter-connected. That's what soil is like. Teaming with life. Unless it's solarized, or water-logged (allows the wrong kind of organisms to flourish, the anaerobic ones, or the wrong form of fertilizers are used leading to acidic or alkaline or salty conditions, etc.

I'm sure there will be other folks adding their replies. In summary, too much watering, lack of mulch, and perhaps less than stellar compost ingredients.

Evapotranspiration computations from a recent irrigation. The Emitter columns exhibit water delivery per plant. I suppose in my case, <4oz (less than a quarter cup) per plant is probably overwatering and allows organics to percolate past and below the primary root zone.

Does the sqft gardening method favor a green house environment? The observed negative impact from what I thought was a small amount of water leads me to wonder if beds should be covered to protect the grow medium from rain which is often delivered larger quantities. Evapotranspiration based irrigation durations yields little to no draining below the bed while after a rain they drain quite a bit.I left room in the beds for mulch, but haven't used any yet primarily to afford me the opportunity to become familiar with drip irrigation. (and gardening itself). I feel I understand the concept and benefit, but felt its absence wouldn't be terminal. Bad call on my part. I've made a lot of those. Maybe my 3rd gardening season will see fewer.

Perhaps we could be more helpful by going back to the beginning and getting a better understanding of the problem.

@GreenGene wrote:...However, across the board, my veggies are low in yield and small in size...

That's a comparative observation based on one year's gardening experience. (One year is what I think GreenGene said) There could be a problem, or it could be the normal fluctuation in garden performance that all gardeners experience over the course of years.

Pictures would be helpful. So would knowing what veggies we're talking about, the time of year they were grown, growth rate (did they reach a certain size and stop, or just grow slowly, etc.), direct seeding or transplants, and any visible abnormalities.

@boffer wrote:.. what veggies we're talking about, the time of year they were grown, growth rate (did they reach a certain size and stop, or just grow slowly, etc.), direct seeding or transplants, and any visible abnormalities.

tomato-(I & D), pepper (hot & sweet), leaf lettuce, celery, chives, parsley, red, white but mostly yellow onion, green bean-pole, okra, beets, garlic, onion-scallion, red, white and yukon potato, carrot, cauliflower, broccoli, rosemary and other culinary herb.I may have been a week late, but tried to adhere to The Almanacs planting guides. This was my first year to start seeds indoors then transplant which seemed to go well. I only lost 1 seedling due to 'transplant cockpit error'. Across the season, I planted 176sqft of 200sqft (78% utilization) totaling a grow potential of 912 plants.Organics were added to the beds prior to planting and I fertilized every couple of weeks using quality, but unsifted composts or Espona Garden and Grow 'Tone' products. The plants reached some point then stopped. Visible abnormalities? The plants yielding smalls (tomatoes, peppers, broccoli, celery, especially onion) were tasty but few. Potato and carrot were closer to expectation. Does abnormality include lack of pollinators? I saw very few bees. A few wasps a couple of ladybugs. I have purchased a mason bee hive and will get the bees and more hives later.

You have all been very helpful. I do not want to consume more of your valuable time and insight. Thanks.